In radio systems, such as the GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), WCDMA (Wide Band CDMA), CDMA 2000, PDC (Personal Digital Cellular) and the like, the movement of a mobile terminal is not usually measured in any way but the operations of the whole radio system are designed so that the data transmission connection works in all conditions. In that case operations are performed as if the terminal moved all the time at a very high rate on the border of the coverage area of two or more base stations in a city during daytime. Consequently, the loading of base stations and the interference level are high and channel changes as great as possible. This wastes resources and power, and increases the interference level because several measuring and signalling operations are performed all too often with respect to what the real movement of the terminal requires.